Ok, wait a second...how do you mean, it seems to run but outputs nothing to the screen? Exactly what happens? How does it look?
If you did the full install, you shouldn't be missing anything. There are various ways to configure X - you could for instance run xfree86setup or xf86config. The latter requires you to enter whatever data it asks for (i.e. keyboard, graphics card, monitor refresh rates etc). You'll probably want to manually edit XF86Config too, for instance in order to tweak mouse settings etc.
It's very basic, and like I said - if you did a full install, you _should_ have everything required to get X up and running (startx).